Thermal protector mounting



July 30, 1968 R. w. SHIFLEY 3,395,297

THERMAL PROTECTOR MOUNTING Filed May 6. 1966 FIG.3

BY F G 5 W Ivar/v17,

United States Patent F 3,395,297 THERMAL PROTECTOR MOUNTING Ralph W. Shifley, St. Louis, Mo., assiguor to Emerson Electric (10., St. Louis, Mo., a corporation of Missouri Filed May 6, 1966, Ser. No. 548,159 4 Claims. (Cl. 310-71) This invention relates to the mounting of a thermal protector on an electric motor in such a position that a reset button on the protector is easily accessible outside the motor.

Heretofore thermal protectors of the resettable type have commonly been mounted on motors by means of screws passing through ears on the protector and into a built up, tapped and threaded area of the stator shell, or by the use of a separate clamp which has had similar ears or flanges, mounted with screws or rivets. The assembly has been complicated, requiring the use of tools and awkward manipulation inside the shell.

One of the objects of this invention is to provide a means for mounting a thermal protector on a motor which is inexpensive to manufacture and easy to assemble.

Another object of this invention is to provide a means for mounting a thermal protector on a motor which will prevent movement of the protector with respect to the motor.

Another object of this invention is to provide a means for mounting a thermal protector on a motor which will allow easy removal and replacement of the protector.

Still another object of this invention is to provide a means for mounting a thermal protector on a motor which will allow the assembly to be done by hand without the use of tools, jig, or fixtures.

Still another object of this invention is to provide a means for mounting a thermal protector on a motor which fulfills all of the foregoing objects and yet provides both a good appearance and a substantially dirt-tight seal around the protruding part of the protector.

Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.

In accordance with this invention, generally stated, a thermal protector mounting means is provided having a supporting structure, such as an electric motor frame band, which is provided with a suitably shaped opening having a protector neck receiving section which, for the purposes of this application will be referred to as the neck hole, and a section offset from said neck hole which, for the purposes of this application, will be referred to as the slot, and a protector bracket having a bezel ring mounted against the outside surface of the supporting structure around the neck hole, a spring arm projecting inwardly from the bezel ring through the slot and a clip arm at the inner end of the spring arm. The protector bracket is preferably made in one piece, of a stiffly flexible material, such as spring steel, so that the clip arm can be sprung away from the bezel ring but will spring back. A thermal protector is mounted with a reset button neck centered in the bezel ring and the clip arm holding it snugly from inside the supporting structure.

In the preferred embodiment the clip arm has a camming detent at its free end, which first, provides a camming surface when the outer edge of the lip of the detent meets the edge of the body of the protector and then, engages a notched area in the protector body, to hold the body against disengagement. The clip arm holds the protector body tight against the undersurface of the frame band which serves as the supporting structure. In this embodiment, the neck hole and slot form a keyhole-shaped opening.

In the drawing, FIGURE 1 is a fragmentary plan view 3,395,297 Patented July 30, 1968 'ice of an electric motor with a thermal protector mounted on it by means of this invention;

FIGURE 2 is a sectional view taken along the line 2-2 of FIGURE 1;

FIGURE 3 is a sectional view taken along the line 3-3 of FIGURE 2;

FIGURE 4 is a view in perspective of a protector bracket of this invention with that part of the bracket which is hidden from view shown in dotted lines; and

FIGURE 5 is a fragmentary plan view corresponding to the view shown in FIGURE 1, with the spring bracket of this invention and the thermal protector removed.

Referring now to the drawings, for one illustrative embodiment of thermal protector mounting means of this invention, reference numeral 1 indicates an electric motor frame band, containing a keyhole-shaped opening 18, made up of a neck hole 5 and a slot 13. Reference numeral 2 indicates a unitary protector bracket made up of a bezel ring 6 with an aperture 12 in it, a spring arm 7, connected to the bezel ring 6 at a bend 11, a clip arm 8, connected to the spring arm 7 at a clip bend 10, and a detent 9 on the free end of the clip arm 8.

Reference numeral 3 indicates a thermal protector which includes a body 17, a neck 4 projecting from one side edge of the body, and a reset button 20, slidably mounted in the neck 4.

The bezel ring 6, which serves the double function of support and bezel, is arched to fit fiat against the external surface of the band 1 around the edge of the neck hole 5. The spring arm 7, at the bend 11, fits closely but easily in the slot 13 and projects radially inwardly therefrom. The protector 3 is mounted tightly between the clip arm 8 and the underside of the band, with the neck 4 of the protector projecting through the hole 5 of the band and the aperture 12 of the bezel ring 6. It will be observed, particularly in FIGURE 3 that the spring arm 7 makes an acute angle with the bezel ring 6, while clip arm 8, in use, is substantially parallel to and flat against the inner edge surface of the body 17 of the protector. In the particular protector shown, which is commercially available, a notch is provided into which the detent 9 snaps, but the detent can also merely embrace an edge of a face of the protector body opposite the spring arm 7.

In the operation and use of this illustrative embodiment of thermal protector mounting means, clip arm 8 and spring arm 7 of protector bracket 2 are passed through the opening 18 radially inwardly of frame band 1 until the bezel ring 6 touches the band, bend 11 lies above slot 13 with spring arm 7 extending through slot 13, and aperture 12 is about concentric with neck hole 5. The neck 4 on the thermal protector 3 is then passed at an angle through hole 5 and aperture 12. The outer lip of the detent 9 is arranged to cam against the contiguous lower edge of the protector body when the protector is tight against the underside of the band. By pushing on the opposite faces of the spring arm 7 of the bracket 2 and of the body 17 of the protector 3, the clip arm 8 is cammed under the body and, when it clears the opposite bottom edge, the detent snaps into the notch in the body, holding the body tight against the band and, because the spring arm is held by the margins of the slot 13, tightly against rotation.

To remove protector 3, it is only necessary to exert a downward and inward force against detent 9 and clip arm 8, to release it, and then to follow the above-mentioned steps in reverse order.

In the embodiment shown in FIGURES 1-4, bezel ring 6 is shown as having a curvature complementary to that of the frame band 1. Bezel ring 6 can have another configuratiomfor special purposes, but generally the bezel ring 6 will conform as closely as possible to the configuration of band 1. It has been found desirable for the bezel ring 6 to form an acute angle with respect to spring arm 7 and for the clip arm to form a convergent angle with respect to the bezel ring to ensure a tighter fit than the fit which would result if the bezel ring 6 and arm 8 were both perpendicular to or at an obtuse angle from arm 7. The spring arm 7 is offset from the bezel ring, and the angle which it makes with the bezel ring is such as to provide substantial alignment between the opening in the bezel ring and the area of the clip arm between the detent and the spring arm. This also positions the spring arm 7 against a side of the protector 3 when in the installed position as shown in FIGURES 1-3, which inhibits rotation of the protector.

By way of illustration and not by way of limitation, a suitable commercial mounting, for mounting a thermal protector measuring .700" x .500" and having a round projection .440 in diameter extending .170 from the body, to a frame band .060" thick with an outside radius of 3.078", can have the following dimensions:

Keyhole opening, overall .575" x .448" Neck hole radius .224" Slot width .255 Protector bracket:

Thickness (22 gauge steel) .028 Bezel ring OD A Bezel ring ID .448" Clip arm and spring arm width .250 Detent height Convergence angle of bezel ring and clip arm unassembled 5.0

Many variations in the construction of the mounting of this invention within the scope of the appended claims will occur to those skilled in the art in the light of the foregoing disclosure. For example, a yoke may be used instead of the uninterrupted bezel ring. This would function to hold protector 3 in place, albeit not so firmly, but would be neither as effective as a seal, nor attractive in appearance.

The detent on the clip arm may be a dimple or simple lip. However the detent shown in FIGURE 4 offers additional protection against rotational movement of the protector as well as eliminating, for the most part, a sharp end on clip arm 8 which might cut the hands of the installer and, importantly, the preferred form serves to cam the clip arm end under the protector body.

The bezel ring may be plated or plated to match or contrast with the frame band, and may carry instructions for the use of the reset button. It can form a part of a name plate on the motor, thereby eliminating the riveting or glueing normally necessary to fasten on a separate name plate. The opening in the supporting structure can take different shapes. For example, if the neck of the protector were square, a rectangular opening could be used, and a square or rectangular bezel ring. These are merely illustrative. f

Having thus described the invention, what is claimed and desired to be secured by LettersPatent is: 4 I

1. A thermal protector mounting for mounting a thermal protector having a body and a neck projecting from the body, comprising a supporting structure having a non-circular opening in it, a protector bracket mounted on said supporting structure in and around said opening, said bracket including a bezel ring mounted on said support at the edge of said opening, said bezel ring having a protector neck-receiving opening in it, a spring arm connected to said bezel ring at a place on the bezel ring offset from the neck-receiving opening of the bezel ring and projecting through the supporting structure opening, and a clip arm connected to the lower end of the spring arm and spaced from an under surface of the supporting structure a distance sufficient to receive between them the body of the protector when the neck of the protector projects into the opening of the supporting structure and the bezel ring.

2. The mounting of claim 1 wherein the protector bracket is a single piece of steel.

3. The mounting of claim 1 wherein the clip arm has a detent on its free end, said detent having a camming lip at its outer edge extending in a direction away from the bezel ring.

4. The mounting of claim 1 wherein the supporting surface is a tubular frame band of an electric motor, the bezel ring is arched transversely to lie flat against the outer surface of the frame band, and the frame band opening has a keyhole configuration with a neck-receiving hole and a slot part, the spring arm extending into and through the slot part.

References Cited UNITED STATES PATENTS 2,523,059 9/1950 Richert 31068 3,215,873 11/1965 Kruger 310 68 3,239,698 3/1966 Clark 310-68 3,350,586 10/1967 Otto 31071 J. D. MILLER, Primary Examiner. 

1. A THERMAL PROTECTOR MOUNTING FOR MOUNTING A THERMAL PROTECTOR HAVING A BODY AND A NECK PROJECTING FROM THE BODY, COMPRISING A SUPPORTING STRUCTURE HAVING A NON-CIRCULAR OPENING IN IT, A PROTECTOR BRACKET MOUNTED ON SAID SUPPORTING STRUCTURE IN AND AROUND SAID OPENING, SAID BRACKET INCLUDING A BEZEL RING MOUNTED ON SAID SUPPORT AT THE EDGE OF SAID OPENING, SAID BEZEL RING HAVING A PROTECTOR NECK-RECEIVING OPENIN GIN IT, A SPRING ARM CONNECTED TO SAID BEZEL RING AT A PLACE ON THE BEZEL RING OFFSET FROM THE NECK-RECEIVING OPENING OF THE BEZEL RING AND PROJECTING THROUGH THE SUPPORTING STRUCTURE OPENING, AND A CLIP ARM CONNECTED TO THE LOWER END OF THE SPRING ARM AND SPACED FROM AN UNDER SURFACE OF THE SUPPORTING STRUCTURE A DISTANCE SUFFICIENT TO RECEIVE BETWEEN THEM THE BODY OF THE PROTECTOR WHEN THE NECK OF THE PROTECTOR PROJECTS INTO THE OPENING OF THE SUPPORTING STRUCTURE AND THE BEZEL RING. 